A Simple Bedtime Habit Could Help You Lose Weight

Going to bed earlier may be associated with weight loss in people with prediabetes. According to a new study, every hour earlier participants went to bed was linked to approximately 590 grams of weight loss over eight weeks. However, researchers stress that the findings do not prove that changing sleep habits alone leads to weight loss.

The study was conducted by researchers at New York University's Rory Meyers College of Nursing. They analyzed data from a randomized trial involving 196 adults diagnosed with prediabetes who typically slept fewer than 6.5 hours a night. The findings were published in the journal Nursing Research.

For eight weeks, half of the participants took part in an educational program focused on nutrition, physical activity and stress management. The other half received the same guidance, along with behavioral support designed to help them gradually move their bedtime to an earlier hour.

Researchers monitored participants' blood sugar levels, sleep and physical activity using sensors, sleep diaries and wrist-worn trackers.

Neither group showed significant improvements in blood sugar levels. Both groups lost weight, but participants who received additional sleep counseling did not achieve a statistically significant advantage over those who took part in the lifestyle program alone.

“We hypothesized that extending sleep duration would improve glucose outcomes and help with weight loss in adults with prediabetes who were not getting enough sleep. However, that did not happen in our study,” said lead author Susan Kohl Malone, an associate professor.

Participants who received help adjusting their sleep schedules did, however, report better sleep quality and less daytime sleepiness. They also gradually began going to bed earlier.

A separate analysis of data from both groups revealed an association between earlier bedtimes and weight loss. Researchers suggest that the explanation may lie in the influence of the body's internal clock on metabolism.

Going to bed later increases exposure to artificial light, which may trigger the body's stress response and affect hormones that regulate hunger. In addition, late-night waking hours coincide with the time when the body's insulin sensitivity is at its lowest.

“By contrast, going to bed earlier may reduce the likelihood of nighttime snacking and help align eating habits with the period when the body is best equipped to metabolize food,” Malone explained.

However, the researchers caution that the study lasted only eight weeks. It remains unclear whether participants will be able to maintain their new sleep schedules and sustain the results over the long term.